Currently marketed domestic spray devices predominately use a liquified propellant to at least in part enable spray generation. A widely used option has been the use of VOCs, such as liquefied hydrocarbons or chlorofluorocarbons, for this purpose. However, it is increasingly recognised that the addition to the atmosphere of VOCs/greenhouse gases may have detrimental environmental consequences.
Sometimes with the aim of reducing the need for VOCs, much research has been performed on high efficiency nozzles for spray devices. Such nozzles may enable spray generation using a reduced level of liquified propellant or even without any liquified propellant at all.
U.S. Pat. No. 5,323,935 (Gosselin et al) describes a nozzle for a spray device in which gas is bubbled into a liquid in a mixing chamber to initiate spray generation. Abplanalp discloses a similar nozzle in U.S. Pat. No. 4,396,152, without disclosing the exact manner of mixing of the gas and liquid. Unfortunately, the nozzles described in both of these publications have limitations in terms of the spray quality attainable and the efficiency of spray generation.
It is an object of the present invention to provide a nozzle for a spray device that enables the production of a spray having good quality (vide infra). It is a further object of the present invention to provide a nozzle for a spray device that enables a good spray rate and/or duration for a given volume of gas used to generate the spray. Preferred embodiments of the invention are of relatively simple design, giving benefits including low cost and ease of manufacturing. Further preferred embodiments are able to operate without the need for large amounts of liquified propellant; indeed certain preferred embodiments are able to operate without the use of any liquified propellant.
The good quality sprays produced by using the present invention are of particular benefit in domestic spray devices, in particular spray devices for cosmetic compositions where a good quality spray equates with good sensory properties for the product.